> There are basically two ways for a system, such as a
> Python function, to indicate 'I cannot give a normal response." One (1a)
> is to give an inband signal that is like a normal response except that it
> is not (str.find returing -1). A variation (1b) is to give an inband
> response that is more obviously not a real response (many None returns).
> The other (2) is to not respond (never return normally) but to give an
> out-of-band signal of some sort (str.index raising ValueError).
>
> Python as distributed usually chooses 1b or 2. I believe str.find and
> .rfind are unique in the choice of 1a.
Doubt it. The problem with returning None is that it tests as False,
but so does 0, which is a valid string index position. The reason
string.find() returns -1 is probably to allow a test:
if line.find("\f"):
... do something
Might add a boolean "str.contains()" to cover this test case.
Bill
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